[FXP] "File exchange protocol"

[FYI] "For your information" (predates the Internet)

[G] "Grin", normally written *G* or <G> to separate it from […]

[g,d&r] "Grins, ducks and runs"; used after a particularly bad joke, […]

[G.I.] or ["government issue"] {n.} An American soldier. * /After the […]

[G2G, GTG] "Got to go", also "good to go"; popularized in […]

[G4Y, GFY] "Good for you".

[gab] See: [GIFT OF GAB] or [GIFT OF THE GAB].

It's a grand life, if you don't tire.

If you want an audience, start a fight.